Feature Request: Thick provisioning for video_p8.hevc

[BeltaKoda]

Hi, I'm working on a docker to automate this conversion for Unraid users. With Unraid, a share path can utilize multiple drives. A common example is the Cache drives on unraid. They are typically SSD storage, but people usually have them set to then use the Array disks (often HDD's) when it's full. When something attempts to create a 50GB file, if 50GB isn't available on the SSDs, unraid will automatically write those files to the Array.

Since dovi_tools doesn't thick provision the video_p8.hevc file (unless I'm blind), if you have 50GB free on your SSD cache, but the original source is 60GB, it will write video_p8.hevc to the SSD cache... but as dovi_tools converts, that file will gain in size until the SSD cache filles, causing an error on the Unraid side, and the process will halt.

Is it possible to have it thick provision the video_p8.hevc file based on the source file? That would solve for this issue.

Thanks in advance!

[quietvoid]

What if you create the sparse file beforehand?
This isn't really something Rust seems to support, and currently file output always truncates the file to 0 bytes when it's open.

It would need to be tested but we also only have a guess as to how large the file ends up being, and it won't be the same as input.

[quietvoid]

@BeltaKoda I need you to test what happens when you run either of these (with a size sufficient to disallow the cache usage)
These are all separate commands, delete the file after each one.

• fallocate -l 60GB test.bin
• touch test.bin and then fallocate -l 60GB test.bin
• truncate -s 60GB test.bin
• touch test.bin and then truncate -s 60GB test.bin

I don't know if creating the empty file first with allow it in the cache, otherwise we have to resort to UNIX system calls.
Since I don't have a setup to test you need to be doing the testing or nothing is going to be achieved.